In this lesson, you will learn about Kotlin functions. Now, let's start by taking a closer look at the syntax, that we created in our "hello world" program. Fun, main, println, "hello world". Okay. What are we actually saying in this program? Let's break it down. Fun is Kotlin syntax for function. A function is a set of Kotlin syntax, that performs a certain task, or routine, or an algorithm. A function will take input, process it, and then return a result. So if we looked at this "hello world" program, then we see that this main function took an input, "hello world", processed it, according to the command println, and then produced a result with the words, "hello world", on the console. You can think of a function as a small program within a program. Your program might have several functions or modules within a program. A function is a self contained group of instructions, that logically fit together, to process our input and produce a result. So we named this "fun main", because every Kotlin program requires a main function at its entry point into the program. The main function controls the main logic. This function in our program has one command line, which is println. Println, which commands the routine to print a value. And the value within our quotes is "hello world". So the result is "hello world". Instead of println, we could have also said print, which prints a value, and then the cursor remained stationary. Or we can use println, which advances the cursor, down one line. So, it's actually two commands in one, print then line. Let me show you an example of that. Print "Hello", print "world". This will give us the same result as println, "Hello world". Println, prints it's arguments, and then adds a line break, so that the next thing you print, appears on the next line. For example, println, "hello world". Next command, println, "hello knowledgecity". And now we can see the results.